const PI = 3.14159265
PI = 3.14 //不能重复定义
console.log(PI)

const user = {
    name: '小邓',
    intro: '程序员'
}

console.log(user)
user.intro = '人生初体验'
console.log(user)

//常量的地址发生变化，算作常量重新赋值
user = {
    name : '秦',
    intro: '发呆'
}
